An oral care appliance using a jet-type fluid flow and mechanical action

ABSTRACT

An oral care appliance using a jet-type fluid flow And mechanical action An oral care appliance comprises: a gas-liquid cleaning assembly which includes a fluid flow pump assembly ( 46 ); a source of liquid ( 50 ); and a source of gas ( 12 ). The pump assembly is in operative communication with the sources of fluid and gas to produce a jet pattern of gas-injected fluid slugs, directed to a nozzle assembly ( 80 ) from which the resulting slugs are directed to the teeth, wherein the individual fluid slugs in the jet flow have a volume in the range of 0.05-0.5 ml per orifice, a diameter in the range of 0.1-2 mm and a repetition rate within the range of 2 Hz to 20 Hz. The appliance further includes a mechanical teeth cleaning assembly, in combination with the gas-liquid assembly, which includes a drive system ( 160 ) and a brush assembly in operative contact with the drive system, the brush assembly having a set of bristles ( 152 ) at the distal end thereof, wherein in operation, the nozzle assembly is positioned within the brush assembly.

TECHNICAL FIELD

This invention relates generally to apparatus for cleaning teeth using acombination of bursts of gas and bursts of fluid to produce a desiredgas/fluid mix, and more particularly concerns a single assembly forproducing both gas bursts and fluid bursts in coordination, as well asan assembly for producing a jet pattern of gas and fluid in anotherembodiment.

BACKGROUND OF THE INVENTION

In systems which produce teeth cleaning with a combination of bursts ofgas and fluid, such as water, it is important that the gas and fluid aremixed in a way to deliver the greatest efficacy of cleaning. In additionit is important to coordinate the timing of these two functions whilestill being relatively simple in structure and operation, andsufficiently small to fit within a specific device footprint. Use ofseparate liquid and gas delivery systems typically have some problemswith timing, as well as space constraints and the need for dual powersources.

SUMMARY OF THE INVENTION

The oral care appliance comprises: an gas-liquid cleaning assembly whichincludes a fluid flow pump assembly; a source of liquid; a source ofgas; wherein the pump assembly is in operative communication with thesources of fluid and gas to produce a jet pattern of gas-injected fluidslugs, directed to a nozzle assembly from which the resulting slugs aredirected to the teeth, wherein the individual fluid slugs in the jetflow have a volume in the range of 0.05-0.5 ml per orifice, a diameterin the range of 0.1-2 mm and a repetition rate within the range of 2 Hzto 20 Hz; and a mechanical teeth cleaning assembly, in combination withthe gas-liquid assembly, which includes a drive system and a brushassembly in operative contact with the drive system, the brush assemblyhaving a set of bristles at the distal end thereof, wherein inoperation, the nozzle assembly is positioned within the brush assemblyor comprises hollow bristles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the apparatus.

FIG. 2 is an elevational view of the opposing side of the apparatus ofFIG. 1.

FIG. 3 is an exploded view of the apparatus of FIG. 1.

FIG. 4 is a partially cutaway elevational view of FIG. 1.

FIG. 5 is a perspective view of the apparatus showing the opposing sideof the apparatus, similar to FIG. 2.

FIG. 6 is a perspective exterior view of an appliance incorporating theapparatus of FIGS. 1-5.

FIG. 7A is a front elevational view of the nozzle assembly portion ofFIG. 6.

FIG. 7B is a cross-sectional view of the nozzle assembly of FIG. 7A.

FIG. 8 is another cross-sectional view of an exit portion of the nozzleassembly.

FIG. 9 is a simplified view of an alternative arrangement to that ofFIGS. 1-6.

FIG. 10 is a simplified view of an appliance using the apparatus of FIG.1-6 or 9 with a power toothbrush.

FIGS. 11A and 11B are cross-sectional and exploded views of a powertoothbrush with a liquid/gas burst system.

DETAILED DESCRIPTION

FIGS. 1-5 show one embodiment of an apparatus, generally at 10, forproducing successive bursts of gas and liquid, such as water, which mixto produce a stream of gas and liquid droplets used for cleaning teeth,especially the interproximal areas of the teeth, accomplishing a“flossing” function. The term gas can include air or other gases ormixtures. Apparatus 10 forms the major part of a complete teeth cleaningappliance, the exterior of which is shown in FIG. 6 and described inmore detail below.

Referring now specifically to FIGS. 1 and 2, apparatus 10 includes angas cylinder 12, which in the embodiment shown is approximately 2.5inches long with an internal diameter of 0.5-1.0 inches. At a distal end14 of gas cylinder 12 is a nozzle 16 through which a mix of water orother liquid bursts and fluid, typically gas, exit, in the form of astream of high velocity liquid droplets. The liquid droplets aredirected toward the teeth of a user, particularly the interproximalarea, for cleaning.

The apparatus includes a motor 20 which in the embodiment shown is a DCmotor, typically with high torque, e.g. 15 Newton meters, although thisvalue is typically achieved after gear reduction. The motor itself thusdoes not have to produce such a value of torque itself. Such motors arewidely commercially available. Various motors are suitable. Motors madeby Mitsumi are for instance examples of a suitable motor. Motor 20includes an output shaft 21 on which is mounted a motor drive gear 22(FIG. 4). In the embodiment shown, there are 8 teeth on the motor drivegear. The number of teeth on gear 22, as with the number of teeth on theother gears, can be varied. Motor 20 is positioned at 24 at the rearupper surface of gas cylinder 12. Motor drive gear 22 engages a first(outer) gear part 26 of a first compound gear 28 located at a first sideof the apparatus. The first compound gear 28 in the embodiment shown ismade of plastic as are the other gears, however it could be made ofother material as well. The first gear part 26 of gear 28 in theembodiment shown has 53 teeth. The motor drive gear 22 in operationrotates it in a clockwise direction. The first compound gear 28 alsoincludes a gear shaft 30 and a second (inner) gear part 32 coincidentwith the distal end of shaft 30, as shown in FIG. 3. In the embodimentshown, the second gear part of the first compound gear has 8 teeth.

The shaft 30 with the second gear part 32 of the first compound gear 28extends through apparatus 10 and mates with a first (outer) gear part 34of a second compound gear 36 positioned on an opposing side of theapparatus. In the embodiment shown, the first gear part 34 of the secondcompound gear has 48 teeth, although this can be varied, as noted above.A second (inner) gear part 38 of second compound gear 36 is positionedadjacent the first gear part 34 on a center gear shaft 37. The secondgear part of the second compound gear has two parts, a first partcomprising a partial set of 8 teeth referred to at 39 spaced aroundapproximately one-half of the circumference of the second gear part anda second part 40 which has no teeth, i.e. the surface is smooth at thebase of the teeth portion of the second gear part. Typically, but notnecessarily, the two parts are each one-half of the second gear part.

The second compound central gear shaft 37 extends back through theapparatus to the first side of the apparatus and engages a peristalticfluid pump assembly 46, which includes a pump 48. Peristaltic pumpassembly 46 includes a first tube section 48 which extends to a fluidreservoir 50. In the embodiment shown, the fluid in reservoir 50 iswater, although other fluids can be used as well. These include variousformulations which assist in cleaning teeth, such as chlorhexidine,hydrogen peroxide-based rinses, mixtures of water, baking soda,essential oils or mouthwash, for example. The peristaltic pump assembly46 also includes a second tube 52 which extends from the pump and abovethe body of the apparatus, in a U-shaped mounting element 54, and thenalong the outer surface of the gas cylinder to a mixing chamber 58 onthe distal end of the gas cylinder.

The second gear part 38 of the second compound gear 36 mates with alinear rack member 62 which is positioned at a proximal end 61 of gascylinder 12. In the embodiment shown, rack member 62 is approximately 2inches long and includes a set of 8 spaced teeth on the upper surfacethereof. The distal end of rack member 62 includes a seal member 64which mates in a fluid tight relationship with the interior surface ofgas cylinder 12. Extending from the distal end of rack 62 at seal 64 andencircling the rack along most of the length thereon is a compressionspring 66. The proximal end 68 of spring 66 is positioned against a stopelement 70 in body portion 20, as shown in FIG. 4.

FIG. 5 is similar to FIG. 2, showing motor 20, and the second compoundgear 36, specifically, the second gear part 38 thereof. FIG. 5 alsoshows a microprocessor controller 80, in the form of a printed circuitboard, for the apparatus, which controls all of the operations thereofand is mounted on an internal frame portion of the apparatus. FIG. 5also shows an on/off power button 82 for the appliance which enables theoperation of the appliance by connecting battery 84, which in theembodiment shown is a lithium-polymer battery, to motor 20. When theon/off button 82 is on, a power light comes on. The appliance alsoincludes an actuation button 86 which, when operated by a user, producesa single shot (burst) of the liquid/gas mixture out the nozzle end 16 ofthe appliance.

In operation, in general, as the motor drive gear 22 turns, rack 62moves rearwardly by action of the partial set of teeth 39 of the secondgear part of the second compound gear 36, the rack moving relativelyaway from the proximal end 61 of the gas cylinder, compressing spring 66against stop 70. Gas enters the gas cylinder through an opening atdistal end 14 thereof. In the embodiment shown, spring 66 undergoes 30mm of compression. Spring 66 in typical operation is compressedsuccessively every 400 to 900 milliseconds, depending on the precise rpmof the motor and the action of the control assembly. It is possible tooperate faster than every 400 ms, even down to 100 ms.

When the second compound gear 36 rotates so that the no-tooth gearportion 40 of the second gear part of compound gear 36 comes adjacentthe rack, such that there is no longer a gear contact between the secondgear part and the rack, and hence no gear holding the rack in position,spring 66 operates to move the rack quickly forwardly, moving the sealedend of the rack forwardly in the gas cylinder, forcing a burst of gasinto the mixing chamber, along with a liquid (water) burst, producedconcurrently by action of the pump 68 or somewhat prior, driven by shaft37 of the second compound gear. Typically, there is one shot of gas perrevolution of the motor shaft, every 400-900 milliseconds (or faster);further, there is approximately 0.15 ml of fluid provided to the mixingchamber per revolution of the motor shaft.

More particularly, in the start sequence of operation, with the powerbutton 82 in an on condition, activation button 84 is pressed by theuser. This begins the intake stroke of the apparatus. In the startingposition, rack member 62 and the seal 64 are fully forward, with thepartial set of teeth 39 of the second gear part of the second compoundgear just engaging the rear end of the rack member 62. Motor 20, asindicated above, initiates action of the entire gear train, resulting inthe rack member 62 moving rearwardly and seal 64 retracting in the gascylinder. This results in compression of spring 66, and the pulling ofgas into the gas cylinder. As the motor and the gear train operates,peristaltic pump assembly 46 operates, causing pump 48 to move fluid,such as water, into the mixing chamber of the apparatus. The outer gearpart 34 of second compound gear 36 includes a magnet 88 (FIG. 5) on anouter surface thereof. As gear 34 rotates, a Hall Effect sensor 90positioned on the internal frame portion of the appliance detects themagnet as it moves past the sensor, and in response starts a softwareimplemented delay time present in controller 80, which turns off motor20 at the end of the time. The timing of the software delay isestablished such that motor 20 is not shut off until after the start ofthe exhaust portion of the operating cycle.

In the exhaust portion of the cycle, when rack 62 and seal 64 are pulledto their rearmost position, with spring 66 fully compressed against stop70 by the action of the partial set of teeth 39, further rotation of thesecond compound gear by action of the motor results in the non toothportion 40 of the second gear part 38 coming adjacent the rack so thatthere is a disengagement between the second gear part 38 and the rack.Rack 62 and seal 64 move quickly forward, driven by the release actionof spring 66. The gas in the gas cylinder is forced rapidly out of thecylinder into the mixing chamber where it mixes with the liquid presenttherein. The resulting liquid/gas mix, in the form of a single burst, isthen forced out of the nozzle.

The Hall Effect sensor software delay times out and the motor is shutoff. The momentum in the gear train allows the second gear part 38 ofthe second compound gear 36 to continue to rotate until the partial setof teeth 39 initially engages with the first tooth or so of the rack 62.This small amount of rotation results in some water being moved into themixing chamber by the continued action of the peristaltic pump. Thetotal volume of water provided for each shot is the amount of waterprovided by a full 360° rotation of the peristaltic pump 48.

At this point, the apparatus is now in a condition to begin the nextshot/burst. The gear train at the end of each operating sequence stopsin the same position after each burst, in accordance with the softwaretimer action operating the motor. The delay timer also acts to preventthe user from operating the unit too rapidly and overheating the motor.It prevents the start of another operating sequence, even though theactivation button 84 is pressed. At the end of the delay time, pressingthe activation button will initiate action of the apparatus, producing asuccessive burst of liquid/gas mixture.

The successive bursts of gas and liquid are brought together in themixing chamber 58, with proper, consistent timing, from which theresulting mixture exits through port 16, directed through the nozzleassembly toward the teeth of the user for cleaning thereof.

FIG. 6 shows the exterior of such an appliance 70. It includes ahandle/receiver portion 72 and an extending nozzle portion 74. Locatedin the handle/receiver portion 74 is a liquid/gas mixtureburst-generating system and a power source therefor, as shown in FIGS.1-5 above. Nozzle portion 74 extends away from the handle and isrelatively slim, in order to conveniently fit into the mouth of a user,for reaching all of the interproximal and gingival areas of the teeth.The nozzle portion terminates in a nozzle exit member 81 having a smallopening 83 in a forwardly extending portion, through which thesuccessive bursts of liquid/gas mixture are directed to the teeth. Theopening in the embodiment shown is approximately 1 mm in diameter,although this can be varied. Further, exit member 81 has a surfaceconfiguration to facilitate proper contact and placement of the exitmember in the interproximal areas of the teeth. The handle/receiverincludes an on/off switch 82 and a control member 86 which when operatedby the user produces the bursts of liquid/gas mixture. While the liquidwill frequently will be water, it should be understood that otherliquids, such as mouthwash and medications, can also be utilized.

In FIGS. 7-8, an elongated nozzle portion which terminates in a nozzleexit member 80 is shown in more detail, including a base portion 91 anda tip portion 92. At the center of tip portion 92 is an exit opening 94through which high velocity droplets are delivered to the teeth of theuser for cleaning when the appliance is positioned properly by the userin the mouth. The nozzle exit member is generally configured to providea guidance function for the interproximal areas. The tip portion 92extends above a surrounding intermediate portion 96 by approximately 1-3mm. In some cases, the exit nozzle member can be slightly tapered, withan exterior diameter of approximately 2 mm The intermediate troughportion 96 tapers slightly away from exit member 24. The intermediateportion 96 terminates in a boundary portion 98 which has a curved uppersurface which defines a lip for the tip portion 92. Additional detailsand advantages of such a structure are set forth U.S. Application61/289,589, which is owned by the assignee of the present invention, thecontents of which application are hereby incorporated by reference.

In one embodiment, a tip portion 98 of the nozzle assembly 80 isseparable from a base portion 94 thereof which extends from body 12.This is shown in FIG. 8. The tip portion is replaceable. The replaceabletip portion of the nozzle has a number of advantages. These include theability to replace the tip of the nozzle due to wear. It also permitsnozzle variations depending on a desired hardness, (or softness) of thematerial. Further, the diameter of the exit orifice of the tip portioncan be changed to alter the characteristic of the liquid droplet spray.

FIG. 9 shows a fluid-based cleaning appliance, generally at 120. FIG. 9shows a more generalized system, capable of providing a spray output, apulse output or a jet output producing bursts of gas at selectivefrequencies, under control of a microprocessor. Typically the fluid iswater, although it could be other liquids, including medications ormouthwash. The appliance 12 includes an appliance body 122, whichincludes a fluid delivery system for producing discrete bursts ofgas/fluid mixtures, including sprays, bursts and jets, and an outlet forthe fluid bursts which proceed through a fluid delivery path 123 in anoutlet member 124, at the end of which is a nozzle assembly 126, asdescribed above, which could include a single nozzle or a plurality ofnozzles. The discrete fluid bursts from nozzle 126 are sufficient toeffectively manage biofilm through mechanical removal thereof, with aresulting reduction in the virulence of microorganisms in the mouth. Thediscrete fluid bursts provide a cleansing benefit greater thantoothbrush bristles alone, because the fluid bursts are able to reachbetween the teeth and along the gum line where bristles cannot reach.The use of discrete i.e. separate, bursts of fluid, as opposed to acontinuous or pulsed jet of fluid, does result in substantially lesstotal liquid volume per brushing event, which may be an advantage as itenhances user comfort and compliance, while maintaining effectiveness.The cleaning event is typically two minutes.

The delivery system includes a displacement pump 130, which isprogrammed in combination with a regulator 132, to provide discretebursts of liquid, typically water, as indicated above, from a tank 134.The liquid could be various medications or mouthwashes. The regulator132 maintains the pressure in the water tank 134 at a specified level.Typically, the pressure is in the range of 40-120 psi, with a preferredrange of 70-112 psi. The water tank holds a cleansing event amount ofliquid, slightly less than 0.2 ml. It has been discovered that a usercan readily tolerate this amount of liquid in a normal cleansing eventof two minutes. The appliance also includes a battery 136, whichoperates pump 130, and a conventional charger coil 138, which is usedwith a charging member (not shown). Controlling the release of liquidfrom the water tank is a valve 140, which is for instance a solenoidvalve, and a timer 141. The appliance also includes a power button 144and a firing button 146, although those two functions can be combined ina single element. A microcontroller 148 controls the operation of theappliance, including an automatic mode of operation for the appliance.The microcontroller can control various fluid dynamics parameters, asdiscussed in more detail below. This is an alternative to thepump/controller system of FIG. 1.

The discrete fluid bursts are predefined in terms of time duration andfiring rate. In a manual mode, the bursts are generated by operatingfiring button 146. Timer 141 controls the duration of the fluid bursts.In one embodiment, the burst time duration range is 0.02-2 seconds, witha preferred time duration of 0.05-0.2 seconds. The firing rate in amanual mode is controlled by the user, which is typically significantlylonger than the burst duration.

In automatic mode, which is controlled by microcontroller 148, the timeduration of the liquid burst will be the same as in the manual mode. Theautomatic mode may be initiated by a programmed sequence of operatingthe on-off switch or by a separate switch member/button for the user tooperate. The firing rate can be automatically controlled orpre-programmed, typically, 0.1-2 seconds, with a preferred range offiring rate of 0.5-1.5 seconds. In some cases, the time duration of theburst and the firing rate may be adjusted by the user by a predefinedsequence of operating the on-off switch. In other cases, the firing rateis permanently set during manufacture.

The advantage of the present system is that the discrete fluid burstsproduced by the system of FIG. 9 provides effective cleaning for theteeth and effective treatment of the gum tissue, but with the totalvolume of liquid being comfortable for the user with a typical cleansingevent time of two minutes, which is an encouragement for regular use.

FIG. 10 shows a variation of the embodiment of FIG. 9, with theappliance having a similar fluid delivery arrangement thereto, or thespecific system of FIGS. 1-6 but with the addition of outlet member 150being driven in a desired physical movement, such as a back-and-forthoscillatory action, with a set of bristles 152 being positioned at theend of the outlet member. Various arrangements can be used for the drivetrain, including mechanical or electromechanical, providing variousmotions which are effective in cleaning teeth by mechanical action, suchas scrubbing. Nozzle 154 or nozzles will typically be positioned withinthe set of bristles 152, but hollow bristles could provide the nozzleaction. The appliance will include a drive train assembly 160, with adrive shaft 162 extending therefrom to drive outlet member. The drivetrain is controlled by microcontroller 164. The drive arrangement couldbe a resonant toothbrush action at a frequency in the range of 230-260Hz for instance.

FIGS. 11A and 11B show another oral care appliance in the form of apower toothbrush 165, with an gas liquid burst system incorporatedtherein. The appliance includes a handle/housing portion 163 and abrushhead assembly portion 165 which includes a bristle plate 166 withbristles 168 at a distal end thereof. The handle also includes a drivetrain system 170 for moving the brushhead in a desired oscillatory (backand forth) motion, which produces a mechanical cleansing/scrubbing ofthe teeth. Any of various arrangements, as indicated above, can providea suitable oscillation action to accomplish scrubbing. The handle alsoincludes a water reservoir 172 and a pump/delivery system 174 forgeneration of the liquid bursts. Burst of liquid are moved to thebristle plate through a fluid path 176, which connects with thebrushhead assembly 164. Positioned within the set of bristles 168 is aspray nozzle 178 at the end of the fluid path. The fluid can also beprovided through hollow bristles or by tubes in the bristle field,either above or below the bristle plate. The power toothbrush isactuated by a power button 180, while the spray system to produce burstsof fluid spray is actuated by a manual actuation button 182. Theoperation of the appliance of FIGS. 11A and 11B is controlled by amicroprocessor controller, shown generally at 184. A battery for poweris shown at 186 and a charging coil at 188. The appliance can also beprogrammed to operate/fire automatically at specific time intervals.

The appliance of FIGS. 10 and 11A/11B has advantages. It is convenientto use a plurality of nozzles. Further, more liquid can be used in asingle brushing event. The gas fluid bursts can be adjusted to achievejust the right amount for truly effective cleansing with the bristleaction. Since the bristles are moving at a desired rate, cavitationaction can occur at the tips of the moving bristles and beyond, into theinterproximal areas, in effect tearing the biofilm apart or from theteeth.

Fluid delivery, gas delivery, fluid/gas mixing and the nozzles describedabove can all be varied as follows:

Fluid pumps can include peristaltic, diaphragm, rotary, impeller,electroosmotic, gear, microannular, cyclone or via a pressurizedair/pneumatic cylinder/container, either positively or negativelypressure driven. Fluid can be passively pulled in through a venturi orvia the Bernoulli effect into a nozzle.

Air pumps can include peristaltic, diaphragm, rotary, impeller,electroosmotic, gear, microannular, cyclone or air can be moved directlyfrom a pressurized air “tank”, either positively or negatively driven.Air can be passively pulled in through a venturi or via the Bernoullieffect over an orifice.

The air and fluid mixing can be achieved through a tortuous pathchannel, array or orifices, a string of periodic/aperiodic orifices,dynamic elements or through direct phase control driving of the pumps(fluid or air).

Various nozzles can be used, including any of the elements to createpulsation or air/fluid mixing through tortuous paths, with the inner andouter dimensions of the part and direction changes within thefluid/air/aerosol path.

For optimal plaque removal and for corresponding oral health benefits,the shear stress provided on the biofilm must exceed the elastic andplastic deformation points of plaque and in addition overcome theadhesive action within the biofilm itself and/or the adhesive forcesholding the biofilm to the dental surfaces. Accordingly, biofilm plaquehas the following mechanical and viscoelastic properties which must beovercome: Young's modulus between 1 Pa and 50 kPa; shear modulus between1.1 and 50 Pa; cohesive shear strengths between 2 and 50 Pa; adhesivestrengths of 5-75 Pa or 0.05-1 J/m²; tensile strengths between 0.1 Paand 6 kPa; adhesion shear stresses of 0.1 to 0.65 J/m²; storage moduliof 1-10 kPa; loss modulus between 0.1-3 nJ/μm³; and failure strains of150-320%. The above ranges depend on the type of the bacterial colonyand age of the plaque and the other mechanical, chemical andphysiochemical properties of the plaque on which it is positioned.

One category of fluid dynamics of the appliances described above,including the toothbrush embodiment of FIGS. 10 and 11A/11B, results ina jet fluid flow with liquid slugs, which is a more laminar-type offlow. The slugs, boundaried pockets of liquid, in a jet stream, areproduced by control of the liquid and gas sources by programming themicrocontroller and by adapting the physical characteristics of thefluid flow channel, as well as use of flexible membrane of elasticmembers affecting the flow. The parameter of the resulting slugs in thejet flow include diameter, volume, slug-to-slug delay, repetition rateand velocity. The volume of the slugs range from 0.05 to 0.5 ml perorifice, with slug diameters of 0.1-2 mm Repetition rates vary between 2Hz to 20 Hz, while the gas/liquid mixture varies between 40-95% byvolume, gas to liquid.

As indicated above, in this embodiment, the fluid flow is in the form ofseparate slugs. This embodiment can also be used with incident anglefrom 0-90°, with 0° being parallel to the tooth surface. Further, anozzle fan angle with a range between 0-10° is possible.

Although a preferred embodiment of the invention has been disclosed forpurposes of illustration, it should be understood that various changes,modifications and substitutions may be incorporated in the embodimentwithout departing from the spirit of the invention, which is defined bythe claims which follow.

What is claimed is:
 1. An oral care appliance, comprising: a gas-liquidcleaning assembly which includes a fluid flow pump assembly, a source offluid, and source of gas, wherein the pump assembly is in operativecommunication with the sources of fluid and gas to produce a jet patternof gas-injected fluid slugs output via at least one orifice of a nozzleassembly from which the jet pattern of gas-injected fluid slugs aredirected to a user's teeth, wherein individual gas-injected fluid slugsin the jet pattern have a volume in a range of 0.05-0.5 ml output perorifice, a diameter in a range of 0.1-2 mm and a repetition rate withina range of 2 Hz to 20 Hz; and a mechanical teeth cleaning assembly, incombination with the gas-liquid cleaning assembly, which includes adrive system and a brush assembly in operative contact with the drivesystem, the brush assembly having a set of bristles at the distal endthereof, wherein in operation, the at least one orifice of the nozzleassembly is positioned within the brush assembly or comprises hollowbristles through which the jet pattern of gas-injected fluid slugs areoutput.
 2. The appliance of claim 1, wherein a gas-to-liquid mixture ofindividual gas-injected fluid slugs ranges from 40-95% by volume, gas toliquid.
 3. The appliance of claim 1, wherein a fan angle of the at leastone orifice of the nozzle assembly ranges from 0-10°.
 4. The applianceof claim 1, wherein the nozzle assembly includes more than one orifice.5. The appliance of claim 1, wherein the brush assembly moves back andforth in an oscillating manner at a selected frequency.
 6. The applianceof claim 5, wherein the selected frequency is in a range of 230-260 Hz.7. The appliance of claim 1, wherein a combined action of the gas-liquidcleaning assembly and the mechanical teeth cleaning assembly produce acavitation action at tips of the set of bristles.
 8. The appliance ofclaim 1, wherein the mechanical teeth cleaning assembly comprises aresonant toothbrush.